b- Once a water sample Is removed from Its place, many of 
its parameters change immediately, temperature and 
dissolved oxygen are some to mention. Thus in situ 
measurements of such parameters are very important should 
correlation be meaningful. 
c- The objective body of water must be undisturbed during 
sampling and during in situ measurements. It is possible 
that the existance of a boat in the objective water 
spoils the tact of the water environment. 
d- It is very important to know where a sample is collected 
from. If the coordinates of the sample are not deter 
mined within a certain accuracy, say + 3 m, there will be 
no meaning of the sampling operation. 
To overcome these four difficulties, namely simultanuity of 
sampling, in-situ measurements, guarding against disturbance 
of the water environment and getting proper coordinates of 
the spot, it is planned in KWPS program to use airborne plat 
form, specifically a PUMA helicopter (Aerospaciale, France). 
THE PLATFORM, THE SENSORS AND THEIR USE 
Aerial photography and scanning operations can be completed 
in a very short time (about 2 hours per coverage in our case). 
It is estimated that about 50 locations are to be visited 
for sampling in situ measurements at 3 depths. If a boat is ; 
dispatched for this mission it may take at least 10 days to 
accomplish the job, which does not match with the speed of < 
R.S. data acquisition. With a helicopter the job can be 
completed in about 8 hours including two landings for refuel 
ling and three other landings for coordinate checking. 
Also with a helicopter a certain flight altitude can be tes 
ted to avoid any disturbance of the water environment. 
As the PUMA helicopter is provided with a computerized Decca 
system, it is very easy to determine the location of a cer 
tain sample within 3 m. In other words, predetermined coor 
dinates of a sampling point can be reached easily within said i j 
accuracy. 
At last, for the measurements of in situ parameters, a floor 
opening in the PUMA helicopter allows sensors be lowered to 
desired depth and record the parameters on board the heli 
copter. For this objective a MARTEK MARK II system is 
selected. Five sensors are connected to one end of a 150 m 
long cable, the other end is plugged in a five dial moni 
toring system. Sensors are designed to sense five parameters, 
namely temperature, dissolved oxygen, pH,conductivity and